Intelligent Propulsion Materials for Rotorcraft Gas Turbine Engine Component Applications

摘要

Rotorcraft gas turbine engines are subject to sand particle ingestion problems during take-off, landing, and hovering operations in sandy desert regions. Although most of the rotorcraft gas turbine engines are fitted with inertial particle separators, they are not efficient in filtering out fine sand particles of size of 75 microns or below. Inlet barrier filters may be efficient in filtering fine particles in the intake air-flow, but they cause engine power loss penalty due to significantly high inlet pressure losses. The sand particles in the air-flow cause severe erosion damage on compressor blades, and molten sand glazing coupled with Calcia-Magnesia-Alumino-Silicates (CMAS) attack on hot-section turbine blades. Due to particle impacts and CMAS attack, the coatings on the blades wear out, form cracks and delaminate over time causing huge maintenance burden for rotorcraft gas turbine engines operating in sandy regions. The objective of this research is to discover a revolutionary, in-situ sensing material system that is capable of monitoring the health of propulsion component materials using co-doped luminescent materials in the erosion resistant coatings or thermal barrier coatings (TBCs) of engine components. This paper presents the research efforts and results from the CCDC — Army Research Laboratory, Vehicle Technology Directorate Director's seedling initiative project that investigated the effectiveness of triboluminescent materials interspersed with blade coatings in a layered form for detecting cracks/fractures that may occur in blade coatings due to sand particle exposure under engine relevant conditions. Use of appropriate instrumentations for in-situ luminescence detection methods to identify cracks/fractures in coatings is also discussed.